Depending on how you define 'Canadian', a lot.
The border patrol captured more people from islamic nations coming into America illegally from Canada then Mexico since 9/11. And that's with less border guards over a much longer border.
So please, don't try to sell me this crap about Tancredo's stance on immigration being about 'National Security'. If it were about national security, he'd realize that terrorists don't care if they come from Canada or Mexico, and that it would be a lot easier to catch terrorist if you let people who only wanted a job in legally.
HEY! Such plain spoken common sense is frowned upon in border threads!
I don't have an opinion one way or the other about Tancredo. He does have an ability to put his foot in his mouth, but he does raise some legitimate concerns. Discussion about limits to immigration isn't off limits in a free republic.
I'd have to agree with those who say that you can't simply throw open the doors to everyone who wants to come here. If you do, you'd probably have more problems with terrorism, not less. And a lot of Americans who pay taxes and contribute to the economy would be hurt.
But your premise is wrong. Don't you know how to do a web search? Look up "Tancredo" and "Canada." You'll find things like this interview with Tancredo in the Toronto Star:
As Tancredo said in an interview with the Toronto Star yesterday, once you seal off your southern flank, your problem becomes your northern flank.
"Right now, we have a problem," he said. "We all know the northern border is porous. People can come through it at their whim." In effect, Canadian "problems" become American "problems" through geographical proximity, he believes.
"If you have an unsecured border, then the policies of your neighbours become yours," he said. "You have a very liberal refugee policy which makes it easy for people to come, especially from the Middle East. As a result it is easy for them to enter into the United States."
You can admire Tancredo or despise him or be indifferent to him, but at least take the time to find out the truth.